Method of investigating subsurface bores and apparatus therefor



May 13, 1969 w. JAGER ET AL, 3,443,642

METHOD OF INVESTIGATING 'SUBSURFACE BORES AND APPARATUS THEREFOR FiledJan. 10, 1967 Sheet of 2 Wolfgang J'ger Alfred Kb'ssling 1 N VEN TOR S'.

B Y Q sfig gar, g a Attorney OR IN ma/zai May 13, 1969 w. JAGER ET ALMETHOD OF INVESTIGATING SUBSURFACE BORES AND APPARATUS THEREFOR FiledJan. 10, 1967 Sheet 13 of 2 Wolfgang J'ger Alfred K'o'ssling INVENTORS.

Attorney 3,443,642 METHOD OF ENVESTIGATKNG SUBSURFACE BORES ANDAPPARATUS THEREFOR Wolfgang Jiiger, Zwenkau, liezirk, Leipzig, andAlfred Kt'issling, Taucha, Bezirk, Leipzig, Germany, assignors to VlEBGeophysik, Leipzig, Germany, a corporation of Germany Filed Fan. 10,1967, Ser. No, 608,353 int, Ci E2lb 23/00 USO Clo 166-315 Claims ABSACTOF THE DISCLOSURE A system for anchoring a flexible element in a subsur=face well whereby geological-investigation instruments can be guidedinto the well along the flexible element and wherein the anchor has ablade receivable in a retrieval sleeve while pawls are spring-biasedoutwardly on the blade so as to be cammed inwardly when the blade isinserted into the sleeve When it is desired to retract the anchor, theblade engages the sleeve via the pawls. One or more spacer rods serve tomaintain the sleeve and anchor in spaced relationship for advance of theanchor system into the bore whereby the pawls engage the wall of thebore for normal cable anchoring prior to retrieval,

Our present invention relates to improvements in geo logical subsurfaceinvestigations and, more particularly, to a system for temporarilyanchoring a flexible element in a subsurface bore for the guidance ofgeological in struments therein as well as to an improved method ofinvestigating such bores,

Background of the invention It has already been proposed to provide forthe geo logical investigation of subsurface bores retrievable an= chorsfor flexible elements such as wires or cables used to guide theinstruments into and along such bores. For this purpose, an anchorassembly of triangular section has been employed whose forward end isprovided with three outwardly swingable claws controlled by a sheavearound which the flexible element is passed, By proper movement of theflexible element the claws can be retracted and the anchorage of thedevice released so that the system can 'be returned to the mouth of thebore, In practice, however, such arrangements have proved to begenerally unsatisfactory, especially when the geological-explorationbore (eg, for geological, geophysical, petrochemical, petrophysical,prospecting, and like investigations) has a diameter of 70 mm. or lessand is inclined to the ver tical, In such cases it has been impossibleto make use of these conventional anchors and, while other expedi entshave been suggested, none have proved to be etfec= tivel Objects of theinvention It is, therefore, the principal object of the present inventiori to provide a system for temporarily anchoring a flexibleelement and a geological-exploration bore which can be used effectivelyeven in small-diameter bores and which can be recovered with facilitytherefrom.

Another object of this invention is to provide an improved system of thecharacter described which is readily recoverable without damage from ageological-exploration. bore, which is of simple and inexpensiveconstruction, which is free from tendency to malfunction and which canbe set up for reuse rapidly and with ease,

Still another object of our present invention is to provide an improvedmethod of investigating geological-exploration bores and especiallybores of relatively small diameter,

dgi i fiili Patented ay 13, 1969 w a in Brief summary of the inventionThese objects and others which will become apparent hereinafter areobtained in accordance with the present invention by an improved methodof investigating a subsurface bore with geological-investigatingapparatus guided therein by a flexible element controlled from the mouthof this bore which has a diameter of, say, less than 70 mm. and isinclined to the vertical (en-g, is of horizontal or obliqueorientation); the method comprises essentially the steps of insertinginto this here a rearwardly open and preferably forwardly closedretrieval sleeve and, following said sleeve, an anchor for the flexibleelement having at least one outwardly biased pawl engageable with thewall of the bore to prevent withdrawal of the anchor, the movement ofthis anchor being terminated short of the sleeve, Thereafter, theapparatus is guided into the bore with the aid of this flexible elementand, upon conclusion of the geological investigation, the systernincluding the anchor and the sleeve is withdrawn. The withdrawaloperation is carried out by shifting the anchor forwardly into thesleeve so that at least this pawl is received therein and lodges againstthe sleeve to lock the latter to the anchor; thereafter, both anchor andsleeve are "retracted from the bore by drawing them therefrom 7 withtheflexible element,

According to another feature of this invention, the sleeve and anchorare advanced into the bore jointly, al= though in sequence and inlongitudinally spaced relation, by a pusher head which may be mountedupon some form of pusher means (e.g. the drill string or rod providedfor this purpose) the head having spacer \means extending past saidanchor into engagement with the sleeve The anchor has a forward bladeportion carrying a multiplicity of such pawls and flanked by the spacermeans (e,g., two spacer rods) so that the entire assembly can be accommodated in relatively small diameter bores.

Although the features and advantages are set forth in detail below, itwill be readily recognized that the harpoon-like system of the presentinvention with its sword-like blade portion carrying the pawls onopposite sides of the blade, affords a positive disengagement of theanchor from the walls by further forward movement of the anchor whilethe sleeve is relatively immovablet When the blade portion is fullyhortsed in the sleeve, it. retains all of the pawls out of engagementwith the walls of the bore so that the sleeve acts as a sheath for thesword-like portion and the most sensitive part of the ap paratus,namely, the resiliently biased pawls. Furthermore, the sleeve serves tomove detritus ahead of its closed end so that loose material cannotblock operation of the pawls following the sleeve I We have also foundit to be most advantageous when the pusher head is provided with means,e.g, an eye, for returning an end of the flexible element to the mouthof the bore, as well as with abutments for preventing swing= ingmovement of the pawls in their opening motion through an angle of morethan The open rearward end of the sleeve thus is able to cam the pawlsinwardly as the anchor is moved into the sleeve by the subsequentpushing operation prior to retrieval of the system, The sleeve can beprovided at this open end with an inwardly extending annular flange inthe form of a locking ring which is engaged by the rearmost pawl to lockthe sleeve to the anchor and enable both to be withdrawn together fromthe bore. Release of the sleeve from the anchor is permitted by openingsadjacent this locking ring whereby a tool can be inserted to disengageeach pawl from the ring and enable the sleeve and anchor to be drawnapart,

Description of the views of the drawing The above and other objects,features and advantages of the present invention will become morereadily ap parent from the following description, reference being madeto the accompanying drawing in which:

FIG, 1 is a longitudinal section of the harpoon device in the process ofbeing pushed into a subsurface bore;

FIG. 2 is a longitudinal section of the anchor harpoon, seated in itsretrieval sleeve, in condition for withdrawal from the bore orsubsequent to such withdrawal;

FIG, 3 is a cross-sectional view taken along the line III-III of FIG. 1;and

FIGS. 4 and 5 are cross-sectional views taken respec tively along thelines IV--1V and VV of FIG, 1.,

Detailed description The retrieval sleeve of the present invention, asshown in the drawing, comprises a tube 2 and a lock ring at its open endor mouth, the purpose of which will become evident hereinafter, Thesleeve is inserted into the subsurface bore, e.g. ageological-exploration hole, in advance of the anchoring harpoon Hwhich, as seen in FIGS, 1 and 2, comprises a blade 4 carrying aplurality of longitudinally spaced pawls 9; the latter are pivoted onrivets 6 attached to the blade 4 on opposite sides thereof. Fur ther,the blade 4 carries abutment bolts or studs 5 which limit to acuteangles (less than 90) the outward swinging movement of the respectivepawls 9, and torsion springs in recesses 7; the springs engage at oneend in aper tures 8 of the blade 4 and resiliently bias the pawls 9outwardly at the other end of each spring The blade portion 4 extendsaxially into a tube portion 12 at the rearward end of the anchor and isaffixed to this tubular portion at 11, e.g. by welding; a return oridler roller, pulley or sprocket 14 is journaled within the tubularportion 12 on a diametrically extending pin 13 which may be generallycoplanar with the blade portion 4 of the anchor H, The tubular portion12 has angularly offset pairs of semicircular openings 15 and 15' in itsend plate 16 (FIG. 4). Through one of these openings a rope, cable,wire, chain or other flexible element 17 passes into the tubular portion12, around roller 14 and out through the other opening 15; the flexibleelement'17 extends through the bore, drilled by conventional techniquesfor geological investigation (e.g. for oil or mining exploration andprospecting) with the usual coring drill or drill string.

One end of the flexible element 17 is preferably attached to an eye 21of a rod head 23. Two parallel spacing rods 20, aflixed to the rod head23 (cf, FIG, 5) are adapted to bear against the retrieval sleeve 2 whenthe latter is disposed forwardly of the rod head in the direction ofinsertion, The spacing rods slide through the openings 15' (or theopenings 15 alongside the roller 14) and bypass the roller, whileflanking the blade 4. At the same time, a guide rod 18 is received inthe hollow rod head 23 so that an abutment pin 19 thereof lies in anotch 22 of the rod head. With forward movement of the head 23, the rods20 are slid into the retrieval sleeve 2 through the lock ring until theyrest against the closed end of the sleeve 2. The guide rod 18 is rigidlyattached to the plate 16 at the rearward end of the anchor H and extendsrearwardly therefrom into the head 23 or the tubular drill string 24serving as a pusher so as to ensure alignment of the assembly duringinsertion of the anchor H into the bore as well as during its movementsubse quently into the sleeve by the pusher string The rod head 23',which is remova'bly fastened to the pusher rod or drill string by athreaded sleeve 26, serves to advance the retrieval sleeve 2 and theanchor harpoon H in succession, but simultaneously and jointly, into thesubsurface bore. When the pusher is withdrawn with its head 23, thespacing rods 20 pull out of the retrieval sleeve 2 and the anchorharpoon H. The end of element 17, which is fastened to eye 21, iscarried along with the head 23 to the entrance of the bore, There,observation and measurement instruments 27. eg radiation detectors,cameras,

temperature-measurement devices, are attached and guided forwardly andbackwardly with the flexible element 17, When this investigation iscompleted, the pusher string may be reinserted into the bore without itsrod head. 23, guided against the abutment pin 19 by the rod 18, andbrought to bear against the anchor H, Blade t of the harpoon is nowshifted further forwardly and into the retrieval sleeve 2 which hasbecome immobilized at the end of the bore, has been blocked by detritusaccumulated in front of the closed end 1, or has been merely re strainedagainst forward movement by its extensive fric tional contact with thewall of the bore,

The pawls 9 are camnied inwardly and disengaged from the walls of thebore against which they had taken an anchorhold during withdrawal of therod head 23 and upon the application of traction to the element 17fastened to the head. The outwardly biased hindmost pawl 9 becomeslocked against the front end of the sleeve at the ring 3, whichconstitutes ah inwardly extending annular flange, since the tip 3' ofthis pawl cannot slide back. over the ring. All of the pawls 9 are urgedagainst the tube wall by the springs 10 and are held thereby out ofengagement with the wall of the bore.

Thus tension applied to element 17 in the rearward direction (arrow 28)brings back the harpoon H as well as the retrieval sleeve 2, locked tothe blade '4. Outside the bore, pawls 9 are pressed inwardly (arrow 29)through two opposite openings 25 of the retrieval sleeve 2 im mediatelyin front of the lock ring 3, whereby the blade 4 can be graduallyremoved from the sleeve 2, A pin 30 may be used for this operation.

The invention described and illustrated is believed to admit of manymodifications within the ability of per sons skilled in the art, allsuch modifications being con sidered within the spirit and scope of theappended claims We claim:

1 A method of investigating a subsurface bore with geologicalinvestigation apparatus guided therein by a flexible element, comprisingthe steps of:

(I) inserting into said bore a rearwardly open retrieval sleeve;

(II) thereafter inserting into said bore an anchor hav ing at least oneoutwardly biased pawl engageable with the wall of said bore preventingwithdrawal of said anchor, and terminating the movement of said anchorinto said boreshort of said sleeve, said flexi ble element being affixedto said anchor and extend ing within said bore;

(III) guiding said apparatus into said bore and re moving it therefromwith said flexible element; and

(IV) subsequently withdrawing said anchor and sleeve from said bore by(a) shifting the anchor forwardly into said sleeve to lodge at leastsaid pawl therein with said sleeve holding said pawl out of engagementwith said wall and said pawl locking said sleeve to said anchor, and

(b) retracting said anchor and said sleeve jointly from said bore bydrawing said anchor therefrom by said flexible element,

20 The method defined in claim 1 wherein said sleeve and said anchor areinserted into said bore in steps (I) and (II) by shifting them jointlytherein in spaced relationship,

St A system for anchoring a flexible element in a sub surface bore,comprising a rearwardly open retrieval sleeve insertable in said here;an anchor for said flexible element, said element being affixed to saidanchor, said anchor being insertable into said bore behind saidretrieval sleeve for temporarily retaining said flexible element in saidbore, said anchor having a forward blade portion receivable in saidsleeve, at least one outwardly biased pawl on said blade portionengageable with the wall of said bore to prevent withdrawal of saidanchor in the direction of the mouth of said bore, said pawl beingcammable inwardly upon advance of said blade portion into said sleeveand lockable thereto for entraining said sleeve with said anchor forretraction of the system from said bore; and means maintaining saidsleeve and anchor in spaced relationship during joint advance thereofinto said bore 4, A system as defined in claim 3 wherein said anchor hasa tubular portion afiixed to and rearwardly of said blade portion, androller means in said tubular portion, said flexible element passingaround said roller means, said retrieval sleeve having an inwardlyextending flange at its open end engageable by said pawl upon insertionof said blade portion into said sleeve.

5., The system defined in claim 3, further comprising pusher means foradvancing said retrieval sleeve and said anchor jointly into said borein spaced relationship.

6, The system defined in claim 5 wherein said pusher means includes apusher head mounted upon a drill string, and said means maintaining saidsleeve and anchor in spaced relationship comprising at least one spacerrod extending longitudinally from said head and flanking said bladeportion while bearing upon said sleeve for ad= vancing the latter intosaid bore upon movement of said head in a forward direction,

7, The system defined in claim 6 wherein said anchor has a rearwardlyextending guide rod received in and. engageable with said head forshifting said anchor through said bore upon advance of said head in saidforward di rection 8s The system defined in claim 6 wherein said head isprovided with means for drawing said flexible element from said anchorto the mouth of the bore upon retrac= tion of said head from said bore,

95 The system defined in claim 3, further comprising roller meanscarried by said anchor and guiding said flexible element, and geologicalinstrumentation guidable in said bore by said flexible element,

10, The system defined in claim 3 wherein said anchor has a rearwardlyextending tubular portion affixed to said blade portion, an idler rollerjournaled in said tubular portion for guiding said flexible elementtherearound, a plurality of said pawls pivotally mounted on oppositesides of said blade portion in longitudinally spaced rela tionship, arespective torsion spring acting upon each of said pawls for resilientlybiasing same outwardly into en gagement with the wall of said bore, anda respective abutment engageable with each of said pawls for limitingthe outward pivoting movement thereof to an angle less than said sleevehaving a closed forward end for the displacement of detritus before itupon its insertion into said bore, and an inwardly projecting lock ringat its open end, said sleeve being provided with an opening adjacentsaid lock ring for permitting said pawl to be disengaged from the lockring upon separation of said anchor from said sleeve; said systemfurther comprising a pusher head mountable upon a drilling string forjointly advancing said sleeve and said anchor into said bore inlongitudi= nally spaced relationship, said pusher head having a pair ofparallel forwardly extending spacer rods adapted to pass through saidtubular portion and flanking said blade portion while bearing upon saidretrieval sleeve for for= ward movement thereof, said head having aforwardly open recess, said anchor having a rearwardly extending guiderod at least partly receivable in said head and an abutment pin adaptedto be lodged in said recess for forward movement of said anchor,

References (fitted UNITED STATES PATENTS 1,734,807 11/ 1929 Hermanmmmmmmmm -s 294--86;24- 1,805,280 5/1931 Gill u 294-45624 2,537,8101/1951 Boadway sssssss l66214 X 3,064,737 11/1962 Quinn 166-214 CHARLESE, OCONN ELL, Primary Examiner,

I, A, GALVERT, Assistant Examiner,

USa Cl, KR,

